As electronic products are recently higher-integrated and smaller-sized, heat dissipation has emerged as a very big challenge. Generally, as a method for heat dissipation, a heat-dissipating plate having a maximized surface area is manufactured through extrusion-molding of aluminum or copper. If this is insufficient, a heat-dissipating structure is subjected to blackening treatment (anodizing) to improve heat dissipation efficiency or an air blower is installed to induce air convection, thereby solving cooling problems of electronic devices. However, the air blower has many problems such as noise, product lifespan, cost, impossible to reduce size, and the like, and thus has a limit in being applied to products.
Currently, with respect to display-related products such as LCD, PDP, and the like, mainly, an aluminum surface is subjected to blackening treatment to increase heat dissipation efficiency of the heat-dissipating plate and thereby to improve cooling efficiency by about 10%. However, in order to upgrade product performance and be applied to next products, current surface blackening treatment does not obtain desirable performances.
Theses problems make it difficult to miniaturize products, improve product performance, and verify designs, whereby products having excellent heat dissipation efficiency have been continuously developed and searched.
Carbon nanotube has been known to exhibit very superior characteristics in a heat-dissipating coating agent for maximizing heat dissipation efficiency. It has been known that carbon nanotube has a distinctive inner structure and excellent heat conductivity and thus heat conduction and heat dissipation effects thereof are very excellent.
However, carbon nanotube needs to be surface treated since dispersibility thereof necessary for being used as a coating agent and adhesive property thereof with a polymer are very low. When the carbon nanotube has low dispersibility and low compatibility, adhesive power and sticking power with a substrate are low, which causes easy film delamination, and thus heat conductivity from the substrate is degraded, resulting in deteriorating dissipation effects.
In order to solve these problems, the carbon nanotube is surface treated to induce functional groups thereon, so that compatibility of the carbon nanotube with a polymer can be improved and physical properties of the carbon nanotube can be enhanced.
Meanwhile, a surface treatment method of the carbon nanotube uses strong acid or strong base to disperse the carbon nanotube in water or an organic solvent. However, a large amount of wastewater generated during this procedure causes environmental burden and the carbon nanotube is damaged during the surface treatment procedure, causing failure in electrical conductivity.